It was the final production for the Andersons (who divorced partway through its run!).
The first episode was actually produced in 1973.
Bain is the only cast member common to all 48 episodes (Landau was absent from only one and Tate missed three).
The quality of scripts under Frieberger eventually pissed off the cast.
It could take up to two years for a new second-season episode to be aired.
Each season had a different opening theme.
Though not interested, Teresa Graves was the original pick for Maya (the shapeshifting alien).

Why Space: 1999 might not be annoying

It inspired another sense of realism in subsequent sci-fi programming.
It became the first post-Star Trek attempt at a weekly science fiction series.
Nice to have some Americans on British science fiction (and a Canadian as the computer voice).
Maya could assume any form for about an hour — though the actual transformation wasn’t shown.
Through a fan-produced episode, Merton reprised her role as Benes to give closure to the series (our September 13, 1999).
Almost none of the cast or crew had any significant problems with Landau and Bain.
It went on to become a true cult classic.

In 2018, Out of 3 Votes: 33.33% Annoying
In 2017, Out of 3 Votes: 66.67% Annoying
In 2016, Out of 1 Votes: 0% Annoying
In 2015, Out of 5 Votes: 40.0% Annoying
In 2014, Out of 10 Votes: 30.0% Annoying
In 2013, Out of 14 Votes: 42.86% Annoying
In 2012, Out of 40 Votes: 22.50% Annoying
In 2011, Out of 9 Votes: 33.33% Annoying
In 2010, Out of 126 Votes: 65.87% Annoying
In 2009, Out of 41 Votes: 48.78% Annoying